This is a question often repeated across the web with a lot of different sites offering plug-ins or generators that will allow a user to change their ‘layout’. There are also many sites that will let you download a ‘template’ that they have created based on pop-culture, music, cars, girls or just about any theme you can think of. I have used a site call pimp my profile they can be found here
You can easily select one of thousands of themes, copy the code and paste it into your about me: section of your profile. You can still have your about me description. Just paste the custom code if front of the normal text that you would use to describe yourself.
You can also customize the design your self with your own images. You can insert flash html, and some limited .class only type CSS. If you’re graphically inclined making a logo and serving the content with your design tweaks can create soem pretty cool looking pages.